1. Technical Field
The present invention relates in general to power distribution within an integrated circuit (IC) chip, and in particular to an apparatus and method for improving DC distribution efficiency for IC applications. More particularly, the present invention relates to an on-chip, multi-plane voltage distribution system for efficiently scaling external power boundaries for use with low-voltage devices.
2. Description of the Related Art
With switching thresholds in the tenths of a volt region for sub-micron IC devices, the trend in power supply technology is toward lower supply voltage levels. To meet such low-power requirements, application board supply voltages as low as 1.2 volts DC are becoming commonplace. While reducing on-chip power consumption, however, such low supply voltages are achieved at a substantial cost in power supply overhead hardware that is required for additional DC-to-DC conversion stages. In addition, the electrical efficiency of low output voltage power supplies suffers due to the additional voltage regulation required for providing application-board-level voltages from DC distribution buses.
Most power supplies are required to support a variety of data processing system requirements in addition to those of internal microcircuits. For a personal computer, such additional requirements may include, for example, the power supply fan, magnetic and optical disk drivers, and input/output (I/O) bus support. Power supplies for larger scale data processing systems may be required to support multiple disk arrays, telecommunication infrastructure, and the like. The vast disparity between the voltage levels required for these applications and the IC chip voltage levels further increases power supply overhead hardware requirements and reduces power supply efficiency.
AC source power supplies operate more efficiently at higher voltages as both a consequence of having fewer voltage level conversion stages and lower current losses. For batteries, the lower current levels afforded by higher operating voltages similarly results in higher output efficiency as well as extending battery life.
To meet disparate power supply requirements from applications that demand high power density, low power consumption, and high efficiency, power supplies for high-level data processing systems, such as network servers, must often be custom designed. Significant development time and resources are required to support such customization for systems having individualized power requirements. Since the design and construction of a custom power supply presumably overlaps the design phase of the data processing system, supply capacity requirements may have to be adjusted, resulting in an overall delay in product development.
From the foregoing, it can be appreciated that a need exists for an on-chip DC power distribution system that will provide relief for the low-voltage conversion requirements of multi-purpose power supplies.
An apparatus and method for providing on-chip voltage distribution and regulation are disclosed herein. In accordance with a preferred embodiment of the present invention, an IC chip includes a source voltage plane having a source supply rail for supplying power to the IC chip and a source ground rail for sinking power supplied therefrom. At least one intermediate ground rail is connected between the source supply rail and the source ground rail to divide the source voltage plane into multiple intermediate voltage planes. The intermediate ground rail serves as a supply rail for a subsequent intermediate voltage plane such that the intermediate voltage planes are connected in series.
All objects, features, and advantages of the present invention will become apparent in the following detailed written description.